期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 99, 期 9, 页码 5830-5835出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.092615399
关键词
-
The mosquitocidal activity of Bacillus sphaericus is because of a binary toxin (Bin), which binds to Culex pipiens maltase 1 (Cpm1), an alpha-glucosidase present in the midgut of Culex pipiens larvae. in this work, we studied the molecular basis of the resistance to Bin developed by a strain (GEO) of C pipiens. Immunohistochemical and in situ hybridization experiments showed that Cpm1 was undetectable in the midgut of GEO larvae, although the gene was correctly transcribed. The sequence of the cpm1(GEO) cDNA differs from the sequence we previously reported for a susceptible strain (cpm1(lp)) by seven mutations: six missense mutations and a mutation leading to the premature termination of translation. When produced in insect cells, Cpm1(lp) was attached to the membrane by a glycosylphosphatidylinositol (GPI). In contrast, the premature termination of translation Of Cpm1(GEO) resulted in the targeting of the protein to the extracellular compartment because of truncation of the GPI-anchoring site. The interaction between Bin and Cpm1(GEO) and the enzyme activity of the receptor were not affected. Thus, Bin is not toxic to GEO larvae because it cannot interact with the midgut cell membrane, even though its receptor site is unaffected. This mechanism contrasts with other known resistance mechanisms in which point mutations decrease the affinity of binding between the receptor and the toxin.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据